diff --git a/src/libstore/normalise.cc b/src/libstore/normalise.cc
index 044eeab942..d535fe2ee6 100644
--- a/src/libstore/normalise.cc
+++ b/src/libstore/normalise.cc
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
diff --git a/tests/parallel.builder.sh b/tests/parallel.builder.sh
index d6d0bedf45..23926110fa 100644
--- a/tests/parallel.builder.sh
+++ b/tests/parallel.builder.sh
@@ -10,7 +10,7 @@ while ! ln -s x $shared.lock; do
 done
 test -f $shared.cur || echo 0 > $shared.cur
 test -f $shared.max || echo 0 > $shared.max
-new=$(($(cat $shared.cur) + 1))
+new=$(expr $(cat $shared.cur) + 1)
 if test $new -gt $(cat $shared.max); then
     echo $new > $shared.max
 fi
@@ -28,5 +28,5 @@ while ! ln -s x $shared.lock; do
     sleep 1
 done
 test -f $shared.cur || echo 0 > $shared.cur
-echo $(($(cat $shared.cur) - 1)) > $shared.cur
+echo $(expr $(cat $shared.cur) - 1) > $shared.cur
 rm $shared.lock